<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>所有 下边框属性在一条声明中</title>
</head>

<style>
    p {
        border-bottom: 6px solid red;
        background-color: lightgrey;
    }
</style>
<p>这是一段文本</p>

</html>